MR Information

MRI is short for Magnetic
Resonance Imaging. It is a procedure used to scan patients to create detailed
images of the body and determine the severity of certain injuries.

MR refers to a
Magnetic Resonance environment. MR images are created by generating strong
magnetic fields. In addition to creating detailed images the strong magnetic
fields also can induce a potentially harmful displacement force and torque,
produce potentially harmful radio frequency heating and create image artifacts
rendering the image useless. Because of these potential risks only certain
medical devices can be used in an MRI environment.

Terms such as "MR friendly" and "MR
compatible" are not recognized by the FDA or ASTM. The following terms and
symbols are what the FDA and ASTM recognize:

MR Safe - used for items that are nonconducting, nonmetallic and nonmagnetic, such as a plastic Petri dish, and pose no known hazards in all MR environments.

MR Conditional - used for an item that has been demonstrated to pose no known hazards in a specified MR environment with specified conditions of use. Conditions
that define the MR environment include static magnetic field strength, radio frequency fields, specific absorption rate and other factors. For MR conditional items, the
item labeling includes results of testing sufficient to characterize the behavior of the item in the MR environment.

MR Unsafe - defines an item that is known to pose hazards in all MRI environments, such as a pair of ferromagnetic scissors.

With the growth of the use of MR technology, the
U.S. Food & Drug Administration [FDA] recognized the need for a consensus
on standards of practice, and the FDA sought out ASTM International [ASTM] to
achieve them. Working with key stakeholders, Committee F04 of ASTM developed
F2503, Practice for Marking Medical Devices and Other Items for Safety in the Magnetic
Resonance Environment. These practices have been put in place for Rhythmlink's
MR Conditional*/CT electrodes.

ASTM International, formerly
known as the American Society for Testing and Materials [ASTM], is a globally
recognized leader in the development and delivery of international voluntary
consensus standards. Today, some 12,000 ASTM standards are used around the
world to improve product quality, enhance safety, facilitate market access and
trade, and build consumer confidence. -courtesy of ASTM.org

Rhythmlink's MR Conditional*/CT Electrodes have been
cleared by the FDA and have demonstrated to be both safe and effective for
their intended use. These electrodes can remain safely on the patient during MR
imaging under specific conditions.